100+ mm and flood risk: Parts of Alberta hit by significant rainfall event
A stalled, low-pressure system is bringing significant rainfall to parts of Alberta, with as much as 100+mm expected in some areas, raising the risk of flooding. There will also be strong wind gusts and a thunderstorm threat on Sunday
Flooding is possible through Sunday as a major rainfall event builds over portions of Alberta.
Rainfall totals could easily exceed 100 mm in some areas. Localized flooding is possible as water levels remain elevated following last weekend’s precipitation.
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Significant rainfall washes into Edmonton
The low-pressure system became anchored at the Alberta and Saskatchewan border on Sunday morning.
The stationary band of heavy rain continues to sit over central Alberta. The Edmonton to Red Deer corridor seeing the heaviest rainfall.
High streamflow advisories are in effect for numerous waterways across the region.
Sunday is the peak of the system, with confidence remaining high that the heaviest rain continues before easing.
Moderate instability and the stationary front may give rise to some thunderstorms across parts of Alberta and southern Saskatchewan. Small hail, gusty winds, and heavy rainfall will be the primary hazards with these storms.
As the low pulls away, we can expect temperatures slowly rebounding as a ridge of high pressure builds midweek.
Cooler temperatures could bring some wet snow above 2200 metres in the Rockies, with the wintry precipitation tapering off by Monday.
By Wednesday, we transition quickly from cold and wet, to warm and dry.
Will this rain set any new records?
Rainfall totals may exceed 100 mm across the Edmonton area.
A swath of 50-75 mm of rain may fall across a region extending from Hinton in the west to Lloydminster in the east, and from Red Deer in the south to Athabasca in the north.
While significant river flooding is not in the forecast, localized flooding will remain a concern, especially in urban areas such as Edmonton proper. Downpours can cause ponding on roadways, as well as swift runoff that can overwhelm storm drains.
Given the extent and duration of the heavy rain expected, Sunday could end up as a top-ten rainiest June day in Edmonton. The gauges have to pick up more than 46.7 mm of rain on Sunday to push the date onto that top-ten list.